Okay, got the mechanic to change the timing belt and this did not solve the problem. He said that it did not skip a tooth and all marks line up (found out that it has Toda branded adjustable intake and exhaust cam pulleys). He then disconnected the exhaust at the Cat converter and when revving it out of gear it did not make quite so much boost. We took it for a drive with it disconnected but the same problem was still there. The mechanic said that it feels if there is a blockage somewhere in the intake. While driving the car it was coming on to full boost at 3000rpm but is struggling to get there.
Things that have been checked so far;
turbo's spin freely,
cat converter is not blocked,
compression tested with all cylinders passing,
spark plugs are fine (the car does not missfire),
This problem is proving difficult to find, I am hoping someone out there might have some more suggestions on what could be causing all of this.